LFZ Postgres Quiz

Question 1

What is PostgreSQL and what are some alternative relational databases?

Answer 1

PostgreSQL is a powerful, free, open source Relational Database Management System (RDBMS). MySQL, SQL Microsoft, Oracle

Question 2

What are some advantages of learning a relational database?

Answer 2

They are widely used

Question 3

What is one way to see if PostgreSQL is running?

Answer 3

Check with top, or sudo service postgresql status

Question 4

What is a database schema?

Answer 4

A collection of tables

Question 5

What is a row?

Answer 5

A set of attributes

Question 6

What is SQL and how is it different from languages like JavaScript?

Answer 6

SQL is a declarative programming language, like css, and HTML

Question 7

How do you retrieve specific columns from a database table?

Answer 7

by using the ‘select’ keyword with the ‘from’ keyword

Question 8

How do you filter rows based on some specific criteria?

Answer 8

with the ‘where’ keyword

Question 9

What are the benefits of formatting your SQL?

Answer 9

readability by humans

Question 10

What are four comparison operators that can be used in a where clause?

Answer 10

=, >,

Question 11

How do you limit the number of rows returned in a result set?

Answer 11

by using the limit keyword at the end

Question 12

How do you control the sort order of a result set?

Answer 12

with the order by key phrase

Question 13

How do you add a row to a SQL table?

Answer 13

with the insert statement

Question 14

What is a tuple?

Answer 14

list of values that corresponds with the tables.

Question 15

How do you add multiple rows to a SQL table at once?

Answer 15

separating tuples with a comma

Question 16

How do you get back the row being inserted into a table without a separate select statement?

Answer 16

with the returning statement with a value of *

Question 17

How do you update rows in a database table?

Answer 17

with the update statement

Question 18

Why is it important to include a where clause in your update statements?

Answer 18

You would change all rows without it

Question 19

How do you accidentally delete all rows from a table?

Answer 19

by forgetting the where statement

Question 20

How do you delete rows from a database table?

Answer 20

with the delete statement

Question 21

What is a foreign key?

Answer 21

A key that links one table to another

Question 22

How do you join two SQL tables?

Answer 22

with the join statement and a foreign key

Question 23

How do you temporarily rename columns or tables in a SQL statement?

Answer 23

by aliasing them

Question 24

What are some examples of aggregate functions?

Answer 24

max, avg, count

Question 25

What is the purpose of a group by clause?

Answer 25

to separate rows into groups